FIELD OF THE INVENTION
The invention relates in general to furnace wall construction and in particular to a new and useful liquid-carrying cooling element for shaft furnace walls especially blast furnace walls.
The inventive construction includes a plate body made of cast iron or similar metal with coolant-carrying tubes which are arranged inside it, which extend substantially parallel to the hot side of the associated furnace, and exit on the cold side. The wall is advantageously equipped with predominantly horizontally extending brickwork supports on the hot side.
Such cooling elements are usually arranged between the steel jacket of the furnace and the furnace lining and are connected to the cooling system of the shaft furnace. On the side facing the inside of the furnace, the cooling elements are provided with refractory material.
In the case of a shaft furnace, the life of a furnace depends mainly on the service life of the refractory lining. Besides the selection of resistant grades of refractory materials, good cooling of the refractory material contributes to the prolongation of the service life.
The cooling method involving the use of liquid-carrying cooling elements has proved to be particularly successful. Contrary to other methods, it brings about uniform, whole-surface cooling of the shaft furnace wall and consequently of the furnace lining as well.
The first lining or the relining of a furnace was previously performed by first mounting the cooling elements, i.e., the metallic plate bodies, on the inner surface of the steel jacket of the furnace and subsequently installing a refractory lining from bottom to top. The annular gap formed was carefully pointed with mortar for heat transfer between the refractory lining and the plate bodies.
The wear on the refractory lining is determined mainly by chemical, mechanical, and thermal stresses. The thermal stress on the plate bodies increases with progressive wear of the lining. Finally, the chemical and mechanical stresses on the plate body reach their maxima on complete loss of the refractory lining.